Success! Check out the functioning solution at: https://codepen.io/torkelv/pen/abbvLWy
Although it's more of a workaround, as there isn't a straightforward method to achieve this.
Utilizing the pluginservice:
Chart.pluginService.register({
beforeRender: function(chart) {
if (chart.config.options.showAllTooltips) {
chart.pluginTooltips = [];
chart.config.data.datasets.forEach(function(dataset, i) {
chart.getDatasetMeta(i).data.forEach(function(sector, j) {
chart.pluginTooltips.push(new Chart.Tooltip({
_chart: chart.chart,
_chartInstance: chart,
_data: chart.data,
_options: chart.options.tooltips,
_active: [sector]
}, chart));
});
}); // disable normal tooltips
chart.options.tooltips.enabled = false;
}
},
afterDraw: function(chart, easing) {
if (chart.config.options.showAllTooltips) {
// prevent animation of permanent tooltips until animation runs at least once
if (!chart.allTooltipsOnce) {
if (easing !== 1) return;
chart.allTooltipsOnce = true;
}
chart.options.tooltips.enabled = true;
Chart.helpers.each(chart.pluginTooltips, function(tooltip) {
tooltip.initialize();
tooltip.update(); // unnecessary since we are not animating tooltips
tooltip.pivot();
tooltip.transition(easing).draw();
});
chart.options.tooltips.enabled = false;
}
}
Add
options: { showAllTooltips: true, }
to the chart configuration.
Reference: https://github.com/chartjs/Chart.js/issues/1861